I'd go with Romania these days on low money.
Yeah, there are some run down areas in Bucharest, random ugly buildings etc
But c'mon it's not THAT bad if it allows you to save a lot of taxes, and grow your online business.
It's cheap and it's safe.
Plenty of big IT companies(Microsoft, oracle, amazon etc)
Internet iirc was third in whole world for average speed. And cheap as chips.
Low taxes, low salaries. Cheap flights to anywhere in Europe.
If you don't like Bucharest after a while you can even try Iasi, Cluj or Timisoara.
Heck, once you setup your residence there, cut with Germany, rent a place and you could even travel the world year round...
About banking, find a firm that will help with the opening.
if you are somewhat decent and the local lawyer comes with you, they'll open no issues.
When thinking of Bulgaria, always remember:
Never ever sign something in cyrillic if you don't understand it.
Have a trusted translator/lawyer with you!
A few friends were scammed big and I am still laughing about it...